please check if the tempo is set to something different than 130 at patch, set or even concert level.
please check if Flex mode is "on" for your playbacks (if it is they'll follow along with tempo info). Unless you want tempo to be variable, this should be OFF!
please describe all controller inputs going into MainStage, as if ANY of these are sending tempo info, and the playback (group) is set to follow, things can and will go wrong, so please check that at concert level, on the timing tab in the workspace, "Get Tempo from MIDI input" is NOT checked.
probably not what you want to hear, but also, please read the manual on the playback plugin. It's a chapter unto itself, and very much worth the read if you're going to be working with backings in MS. All of the above is in that chapter.
I don't know if this newer post from you means you've solved the other issues you were having with playbacks or not. Maybe you're just trying another template as you're creating stems for backings... let's see how far you get!
Logic X (latest), MainStage (latest), macOS v10.13 High Sierra (latest)
15" touchbar MacBookPro 2017, 16 GB RAM + 2x MacMini i7, 16GB RAM utilizing Vienna Ensemble Pro 6